Peshmerga forces advance in the east of Mosul to attack Daesh militants in Mosul, Iraq, October 18, 2016. REUTERS/Thaier Al-Sudani

AMMAN, Oct 18 – The Syrian army accused the U.S.-led coalition of planning to allow safe passage into Syria for Daesh militants fleeing the Iraqi city of Mosul, saying it would combat this with all forces at its disposal.

The U.S. is leading a coalition against Daesh in Syria, and there was no immediate comment from its representatives in Washington and Baghdad. The Russian-backed Syrian army is also fighting Daesh in a separate campaign in Syria.

Mosul is the ultra-hardline Sunni jihadists’ last stronghold in Iraq, and Iraqi government and Kurdish forces on Tuesday announced progress in the first 24 hours of an offensive to retake the city, backed by air and ground support from the coalition.

The army command in Damascus said in a statement on Tuesday that, under a plan spearheaded by Washington and Riyadh, roads would be secured to allow the militants to create “new battleground realities” in eastern Syria.

The Syrian army statement did not say what it based its assertion on.

The assault on Mosul has been in preparation since July, and at stake for U.S. President Barack Obama is his hoped-for legacy of seizing back as much territory as he can from the jihadists before he leaves office in January.

U.S. officials acknowledge gaps and risks in the plan, amid worries that defeat of Daesh in its de facto Iraqi capital could give way to sectarian score-settling and land grabs in the country’s ethnically mixed north.

Daesh militants in Syria have supply routes into Mosul where they cross into Iraq from territory they control in oil-rich Deir Zor.

They still control the Syrian city of Al-Bukamal, near a border crossing into Iraq’s Anbar province and long a major supply and communications lines for the group between the two countries.

IS also exploits the tribal links between Bedouin tribes in both Iraq and Syria to its advantage.

“Any attempt to cross the border is an attack on the sovereignty of Syria… and would be dealt with all forces available,” the army statement released on state media said.